Hadoop system

最近上Hadoop的官網看到這段話

The client framework will implicitly associate the user identity with the connection to the name node, reducing the need for changes to the existing client API. It has always been the case that when one operation on a file succeeds, the operation might fail when repeated because the file, or some directory on the path, no longer exists. For instance, when the client first begins reading a file, it makes a first request to the name node to discover the location of the first blocks of the file. A second request made to find additional blocks may fail. On the other hand, deleting a file does not revoke access by a client that already knows the blocks of the file.

我寫中文比較能表示意思，表示當有人reading a file，同時有人做刪除或修改的動作，reading會錯誤。
表示說Hadoop並未做任何lock的動作....所以如果有read file from HDFS，記得要做Error handle。